1. Field of the Invention
This invention relates generally to processors and, more specifically, to a Reduced Instruction Set Computer (RISC) based microcontroller having an extended operating voltage range.
2. Description of the Prior Art
Presently, Reduced Instruction Set Computer (RISC) based microcontrollers operate at a voltage level of between 2.5 volts to 6.5 volts. This limited voltage range eliminates the possible use of RISC based microcontrollers without external voltage regulation in many applications. By increasing the operating voltage range of a RISC based microcontroller, one would increase the possible usage of these types of microcontrollers into different regions of application. For example, by raising the operating voltage of the RISC based microcontroller to 9 volts or 12 volts, one may use a RISC microcontroller without external voltage regulation in applications where an inexpensive 9 or 12 volt battery is the main source of power.
Therefore, a need existed to provide an improved RISC based microcontroller. The improved RISC based microcontroller must have an extended operating voltage range. The improved RISC based microcontroller must have an extended operating voltage range of approximately 2 volts to 18 volts thereby allowing the usage of these types of microcontrollers into many different types of applications.
In accordance with one embodiment of the present invention, it is an object of this invention to provide an improved RISC based microcontroller.
It is another object of the present invention to provide an improved RISC based microcontroller that has an extended operating voltage range.
It is still another object of the present invention to provide an improved RISC based microcontroller that has an extended operating voltage range of approximately 2 volts to 18 volts thereby allowing the usage of these types of microcontrollers into many different types of applications.
In accordance with one embodiment of the present invention, a processor having an extended operating voltage range is disclosed. A processing unit, preferably a RISC based microcontroller, is coupled to a processing unit voltage regulator. The processing unit voltage regulator is used for controlling an operating voltage of the processing unit. A control unit is coupled to the processing unit voltage regulator and to the processing unit for setting a regulated voltage level for the processing unit voltage regulator. A voltage supply coupled to the control unit and to the processing unit voltage regulator is provided and is used for supplying the operating voltage for the processing unit. The operating voltage is characterized as a variable voltage range with a selectable upper and lower operating voltage limits. Furthermore, the processor will not be subject to a current penalty in the selection of one operating voltage over another.
The processor may further have a high voltage input/output (I/O) port coupled to the voltage supply. The high voltage I/O port is used for allowing peripheral devices which operate at the operating voltage supplied by the voltage supply to be coupled to the processing unit. High voltage interface logic is coupled to the high voltage I/O port and the processing unit for allowing communication compatibility between the peripheral devices coupled to the high voltage I/O port and the processing unit.
The processor may further have an I/O regulator coupled to the voltage supply. The I/O regulator is used for supplying a regulated I/O device voltage level. This regulated I/O voltage may or may not be the same voltage level as the regulated processing unit voltage.
A regulated I/O port is coupled to the I/O regulator for allowing peripheral devices which operate at the regulated I/O device voltage level to be coupled to the processing unit. Interface logic is coupled to the regulated I/O port and the processing unit for allowing communication compatibility between the peripheral devices coupled to the regulated I/O port and the processing unit.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawing.